Re: [PATCH v4 00/19] LSM: Module stacking for SARA and Landlock

[Casey Schaufler]

On 9/21/2018 8:02 PM, Kees Cook wrote:
> On Fri, Sep 21, 2018 at 4:59 PM, Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote:
>> v4: Finer granularity in the patches and other
>>     cleanups suggested by Kees Cook.
>>     Removed dead code created by the removal of SELinux
>>     credential blob poisoning.
> Thanks for the splitting, this really does make it easier to review
> (at least for me). I think this looks really good, though obviously
> I'd like to refactor it slightly on top of my series. :)

Whichever goes on top is fine with me. What's one
more patch set merge, after all?

> One additional thought I had was about the blobs allocations: some are
> separate kmem caches, and some are kmalloc. I'm thinking it might make
> sense to use separate kmem caches for two reasons:

I had seriously considered doing that. I can't see any reason
not to. It's something that could be done at any time, and with
all the other things that had to change it just didn't get in.

> - they're going to always be the same size and are regularly
> allocated/freed, so it may offer a performance benefit.
>
> - they're explicitly not supposed to be exposed to userspace, so
> hardened usercopy would protect them if they were not kmalloc()ed.
>
> I'm excited about getting this landed!

Soon. Real soon. I hope. I would very much like for
someone from the SELinux camp to chime in, especially on
the selinux_is_enabled() removal.

On a somewhat related note, I will be out for the first three
weeks of October, returning just in time for the Linux Security
Summit in Edinburgh. My connectivity will be severely limited.
I don't expect to accomplish anything while I'm out.